Long-term Mortality Worse for Black vs White NSTEMI Patients, Linked with Treatment Discrepancies

 

Among older patients treated for non-ST-segment elevation myocardial infarction (NSTEMI), black patients are less likely than their white counterparts to receive guideline-based acute medical treatments, coronary revascularization, and newer antiplatelet therapies, according to a study published online July 7, 2014, ahead of print in Circulation. Short-term mortality is similar between the groups, but risk of long-term death is greater for black patients. 

Methods
Investigators led by Eric D. Peterson, MD, MPH, of Duke University Medical Center (Durham, NC), examined longitudinal care records—created by linking data from the CRUSADE registry with corresponding Centers for Medicare and Medicaid Services (CMS) administrative data—to determine mortality and readmission rates in 40,500 patients. Of the patients included in the analysis, all were at least 65 years old and 7.7% (n = 3,116) were black. 
Analysis was limited to patients enrolled in the CRUSADE trial from February 15, 2003 to December 31, 2006, who had CMS data through the end of 2008. 
 
At baseline, black patients were younger, more often female, and had higher rates of prior heart failure, stroke, diabetes, hypertension, renal insufficiency, and ongoing dialysis than white patients. They were also less likely to have additional private insurance coverage and more likely to present with heart failure. 
 

 
Less Aggressive Treatment for Black Patients

Black patients were less likely than white patients to undergo diagnostic cardiac cath (54.0% vs 60.7%) and revascularization with PCI (23.8% vs 32.1%) or CABG (5.7% vs 9.2%; P < .001 for all). 

Rates of in-hospital aspirin and heparin use were comparable between groups, but black patients were less likely to receive glycoprotein IIb/IIIa inhibitors (P < .001), clopidogrel (P < .001), and beta-blockers (P = .043) than white patients. They were also less likely at discharge to be given clopidogrel (P < .001) and ACE inhibitors (P = .011), though receipt of aspirin, beta-blockers, and lipid-lowering agents was similar to that in white patients. 

Race Affects Long-term Mortality

Though black patients had comparable 30-day mortality with white patients, black race was associated with higher long-term mortality (table 1). 

Table 1. Mortality Over Time by Race

 

Black Patients 

(n = 3,116) 

 

White Patients 
(n = 37,384) 

P Value

30 Days

9.1%

9.9%

.13

1 Year

27.9%

24.5%

< .001

2 Years

37.7%

33.3%

< .001

3 Years

44.6%

40.5%

< .001


After adjustment for clinical risk factors, there was a mortality advantage for black patients at 30 days (HR 0.80; 95% CI 0.71-0.92), whereas after 30 days, adjusted mortality equalized between black and white patients (HR 1.00; 95% CI 0.94-1.07). Additionally, MI size did not account for the different survival rates. 

In the 36,190 patients with available data, crude readmission rates were higher at all study time points for black vs white patients (table 2). With adjustment, these differences disappeared at 30 days (HR 1.02; 95% CI 0.92-1.13) and 1 year (HR 1.05; 95% CI 1.00-1.11).

Table 1. Readmission Over Time by Race

 

Black Patients  

White Patients   

P Value

30 Days

23.6%

20.0%

< .001

1 Year

62.0%

54.6%

< .001

2 Years

73.1%

66.7%

< .001

3 Years

78.9%

73.5%

< .001

 

There were no significant interactions between race and gender, age group, diabetes, or income level in short- and long-term readmission rates. Black patients were also more likely to be readmitted for heart failure during long-term follow-up than their white counterparts (adjusted HR 1.13; 95% CI 1.03-1.24).

‘Multifactorial’ Explanation for Long-term Disparity

The authors describe the causes for differences in treatment and outcomes between black and white patients as “multifactorial” including those related to environment, comorbidities, and behavior. 

Higher readmission rates in black patients could be due to “poor medication adherence postdischarge, limited access to follow-up care, or poor quality outpatient management,” they write. Additionally, the authors say that the leveling of “readmission risk with adjustment of patient characteristics reflects the increased burden of comorbid disease in blacks more so than in whites at the time of their event.” 

Furthermore, factors such as the quality of social support and availability of home ambulatory care might contribute to the increase in mortality for black patients after 30 days, the authors suggest. 

Ron Waksman, MD, of MedStar Washington Hospital Center (Washington, DC), told TCTMD in an email, “White people may have more trust in caregivers and also usually [present] with fewer comorbidities.” These factors, he explained, may make it more attractive for caregivers to offer more invasive care. 

Implicit Physician Bias May be at Fault

In an editorial accompanying the study, Clyde W. Yancy, MD, MSc, of Northwestern Memorial Hospital (Chicago, IL), criticizes the parameters used by the study authors “as surrogates for socioeconomic status and more broadly the social determinants of health,” calling them “crudely representative.” 

In regards to the fall-off in survival experienced by black patients, Dr. Yancy implicates the “lack of a high level of subscription to evidence-based intervention,” adding that the disparity will continue unless physicians confront the social context of their clinical choices. “None of us are overtly biased but all of us… are persuaded by our preconceived stereotypes and implicit bias,” he said, pointing out that surveys show approximately three-fourths of all contemporary medical students demonstrate a “decided bias” favoring white over nonwhite patients. 

“We cannot reprogram our innate tendencies, but we can manage our decisions,” Dr. Yancy states. 

 Importantly, the study data are over 5 years old, he notes, expressing hope that practice patterns have changed. 

 Dr. Waksman said awareness is the first step. “We are trying to close the gap by first recognizing that there is a gap,” he concluded. “[We are also implementing] educational programs so that hopefully 5 years from now we will be in better position than we are today.”

 

Sources
  • Mathews R, Chen AY, Thomas L, et al. Differences in short-term versus long-term outcomes of older black versus white patients with myocardial infarction: findings from CRUSADE. Circulation. 2014;Epub ahead of print. 

  • Yancy CW. Disparate care for acute myocardial infarction: moving beyond description and targeting interventions [editorial]. Circulation. 2014;Epub ahead of print.  

Disclosures
  • Dr. Peterson reports receiving research funding from the Eli Lilly and Ortho-McNeil-Janssen Pharmaceuticals and consulting for AstraZeneca, Boehringer Ingelheim, Genetech, Johnson &amp; Johnson, Ortho-McNeil-Janssen Pharmaceuticals, Pfizer, and Sanofi-Aventis.
  • Drs. Yancy and Waksman report no relevant conflicts of interest.

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